Safety monitoring system for a people conveyor

ABSTRACT

People mover ( 2 ) comprising an endless tread belt ( 6 ) formed from several tread elements ( 4 ) connected to one another, which is driven by a drive unit about a first and second reversal point ( 22 ), and a side skirt ( 24 ) moved along with tread belt ( 6 ), the side skirt ( 24 ) comprising flange elements ( 28 ) joined to the tread element ( 4 ) and bridge elements ( 30 ) connected movably relative to flange elements ( 28 ). A sensor ( 38 ) is arranged adjacent to the side skirt ( 24 ), the sensor ( 38 ) having a limited detection range perpendicular to the circulation direction of side skirt ( 24 ), and a plurality of marking elements are arranged in a line on side skirt ( 24 ) along the circulating direction having a limited width perpendicular to the circulating direction.

The invention pertains to people movers comprising an endless tread beltformed from several tread elements connected to one another, which isdriven by a drive unit about a first and second reversal point, and aside skirt moved along with the tread belt, the side skirt comprisingflange elements joined to the tread belt and bridge elements connectedmovably relative to the flange elements.

Such people movers are known from, for instance, DE 101 56 991 A1 and DE101 56 992 A1. Moving walkways and escalators are typicalrepresentatives of people movers with a circulating endless tread belt.Thus an escalator typically comprises a plurality of mutually connectedstep bodies, which together form the tread belt. They are driven by adrive motor about an upper and a lower reversal point, for instance, inthe form of a reversing sprocket wheel, reversing guide track or areversing shield, etc. In a similar manner, moving walkways can compriseseveral palette bodies joined to one another, likewise drivencirculating around two reversal points. For moving walkways, the treadbelt is usually called a pallet belt, while it is usually called a stepbelt for escalators. The tread elements for both are typically connectedat their sides to conveying chains, which typically also transfer thedrive force of the tread belt. Thus, for instance, one of the reversingchain wheels can simultaneously be constructed as a drive wheel.Alternatively, other drive units, such as linear motor drives can beconnected in the moving forward zone or the return zone of the conveyingchains. In principle, it is also possible to provide drive units thatact directly on the individual tread elements and for which the chainrepresents primarily only the connection between the individual treadelements.

As a matter of principle, great attention is given to the safety ofpassengers for such people movers. In the previously described type ofpeople mover with a concurrently moving side skirt, the risk existingfor a fixed skirt that parts of clothing or limbs of passengers might bedrawn in between the moving tread belt and the stationarily mountedskirt is avoided or considerably reduced. The moving side skirttypically runs at the top in a fixed trim piece or in the balustrade.Moreover, the movable side skirt typically consists of several parts,some of which are stationarily arranged laterally on the tread elementsin the form of lateral flange elements, or are movably arranged betweenthese flange elements in the form of bridge elements and are placed, forexample, on the step chain in order to reliably close an otherwise openspace between the flange elements. Slideways are typically providedbetween the flange elements and the bridge elements. In particular, theflange elements and the bridge elements can run relative to one anotherin a tongue and groove arrangement. For installation, the bridgeelements can be removed relatively easily. Of course there is a certainrisk that the bridge elements may be broken away due to vandalism. Insuch a case, a “hole” circulates along with the movable side skirt,which is highly dangerous. If, for example, a body part is in such ahole in the area where the tread belt enters the floor, then the edge ofthe subsequent flange element acts as a crush edge and severs this bodypart. For this reason, it is absolutely required that the escalator bedeactivated immediately whenever such a bridge element is missing fromthe movable side skirt.

An escalator with movable side skirt, wherein the side skirt is formedfrom side skirt elements movably connected to the escalator steps isknown from U.S. Pat. No. 4,470,497. A sensor that can detect the absenceof side skirt elements is additionally provided.

For people movers with tread elements, there are also typically varioustypes of sensors, for instance, for detecting completely missing treadelements, or sensors that can detect a shift of the tread elements outof the correct position. Thus, for instance, in case the plastic runningsurface provided on the step shaft rollers is lost, there may be asubsidence of the step downwards, or a rising of the step above itsordinary position in other parts of the turnaround area. For thesepurposes a plurality of sensors are provided, each being able to detectone typical actual error. Thus, the sensors for detecting missing treadelements are typically located in the return strand of the people moverand bring about an interruption of the operation of the people mover assoon as a missing tread element is detected. Other sensors detect, forexample, a shifting of the step shaft, in order to be able to detect ashifting of the step upwards or downwards.

The problem of the invention is to make available a simple andeconomical sensor means for detecting missing bridge elements andmissing tread elements as well as for detecting that they are out oftheir correct position. According to the invention, this problem issolved in that, in the people mover as described above, a sensor isprovided which is arranged adjacent to the concurrently moved sideskirt, the sensor having a limited detection range perpendicular to thecirculation direction of the side skirt, and with marking elementsarranged in a line on the side skirt along the circulating directionbeing provided, the marking elements having a limited widthperpendicular to the circulating direction.

With this type of sensor means, the monitoring of missing tread elementsand missing bridge elements is integrated, with the absence of a flangeelement connected to a tread element serving as an indicator of theabsence of the entire step. The flange elements are either formed in onepiece with the tread elements or are permanently bolted to them, so thata situation in which a flange element is present but the actual treadelement is missing is inconceivable The limited detection range of thesensor perpendicular to the circulation direction of the tread, incombination with the limited widths of the marking elementsperpendicular to the circulation direction makes it possible to generatean alarm signal not only if a part of the side skirt or a step iscompletely absent, but also if there has been a shifting of this partbeyond a certain amount. The detection range of the sensor and the widthof the marking element are favorably selected such that a shifting ofthe step element, in particular, can occur only to the extentpermissible according to regulations, and an error report takes placewhenever this permissible amount is exceeded.

The sensor is preferably arranged at particularly critical points, forinstance, just in front of the area where the belt enters the floor, inorder to prevent a “hole” from entering the return area. Anotherpreferred point is in the vicinity of the emergence area of the treadbelt in order to prevent a belt in which a tread element is missing frommoving into the forward motion area. Those areas in which there is agreater tendency for a shifting of the tread to occur are also relevant.Let it be explicitly pointed out that this type of sensor means can alsobe employed for people movers with moving side skirts that do not haveflange elements mounted on the tread elements and bridge elements, butmerely concurrently moved side skirt elements as provided, for example,in U.S. Pat. No. 4,470,497, already mentioned. One can imagine providingthe marking elements alternately on the tread elements and the sideskirt elements, so that a comprehensive error detection can beaccomplished in that way as well.

Preferably, at least one sensor is provided on both sides of the treadbelt to detect missing tread elements and missing bridge elements. Theprobability that a tread element is missing and at the same time thatboth flange elements of this tread element remain in the side skirt andare detected by the sensor approaches zero.

The concurrently moved side skirt consisting of flange elements andbridge elements has an exposed visible side facing the tread elementsand an oppositely oriented side, which is not perceived by the user ofthe people mover. The sensor is preferably arranged on the side otherthan the visible side, in the “interior” of the people mover.

On each of the flange elements and/or the bridge elements of theconcurrently moved side skirt, a rib is preferably provided, whichserves for the detection of the flange element or bridge element by thesensor and is arranged on the side other than the visible side of theconcurrently moved side skirt. The rib can either be detected directlyby a sensor or, alternatively, the rib can contain or have markingelements that are detected by the sensor. The rib can also beconstructed as a reinforcement element for the otherwise relatively thinmaterial of the side skirt.

The ribs are preferably arranged such that, in the linear area of thepeople mover, they are arranged in series essentially along a straightline, with the sensor constructed such that it detects interruptions inthe series of ribs or of marking elements. “Linear area” is understoodas an area in the tread belt of the people mover in which the treadelements are arranged essentially along a straight line. For escalators,this is typically the conveyance area or the inclined area of theforward motion area of the people mover, in which the tread elements areexposed in order to convey the passengers, or a linear area in thereturn area of the people mover in which the tread elements are conveyedback. For escalators, there is a distinction between the followingareas, starting with the lower landing in the outgoing area: lowerlanding, lower transitional area, inclined area, upper transition area,and upper landing, the direction of motion in the upper and lowerlanding being essentially horizontal. The situation for moving walkwaysis similar. The sensor is preferably arranged in such a linear area. Itcould also be arranged, however, in an area in which the series of ribsdo not form a straight line, but rather an “angular” curve.

Preferably, a noncontact sensor is provided. A magnetic sensor isparticularly preferred. Alternatively, however, contact sensors can alsobe provided which, for instance, run with the side skirt by means of aroller or a carriage and open or close a contact in case of the absenceof a flange element or a bridge element. Alongside magnetic or inductivesensors, alternative noncontact sensors are, for example, capacitivesensors and optical sensors. Ultrasonic sensors can also be provided. Itis particularly preferred if the sensors are constructed as proximitysensors, i.e., are able to detect the distance of the side skirt awayfrom the sensors. An excessively large lateral movement of the sideskirt, and thus of the entire tread belt, is an indicator of excessiveplay in the people mover, caused by wear or incorrectinstallation/adjustment. In both cases it is advisable to check thesystem. It is necessary in general to take the entire system out ofoperation immediately upon detecting a missing part, in order to avoidinjury to people or damage to the system. It is also advisable to relaysignals of the monitoring means via, for example, the system controllerto a maintenance center which engages customer service in case of ashutdown of the system or takes similar steps in case a proximity sensorascertains irregularities in the operation of the system that do notautomatically lead to a shutdown of the system.

The flange elements and the bridge elements are preferably produced fromaluminum material, and it is especially preferred that the ribs beconstructed in one piece with them. It is additionally preferred that atleast one clip made of spring steel be provided on the rib of eachflange element and of each bridge element. Aluminum material can beproduced relatively economically, particularly with the pressure-castingmethod. It is also a relatively lightweight material, which isparticularly preferred for such systems. Moreover, the tread elementsare often produced from pressure-cast aluminum, and it is especiallypreferred that the flange elements be produced in one piece with thetread elements. Pressure-cast aluminum material can in principle bedetected by the magnetic sensors preferred by the applicant, and thereare also inductive sensors for nonferrous materials. In such a case, theribs are preferably not provided to be continuous, but are insteadinterrupted. The sensor detects the difference rib/no rib and generatesa dynamic signal. Then, however, it is necessary to provide asufficiently high rib. That is frequently not desired for reasons ofspace. Instead it can be more economical to provide, in or on the rib, amarking element that can be detected by the sensor. It is particularlysimple for this to be a clip made of spring steel, which may have barbs,and can be pressed onto the rib relatively easily. For magnetic sensors,a clip made of magnetic spring steel is desirable.

The rib preferably extends over essentially the entire length of theflange element or the bridge element. The clips are preferablyessentially half as long as the corresponding rib or flange element orbridge element in the extension direction of the marking element. Incontinuous operation of the people mover, this design of the length ofthe marking elements or this interrupted arrangement of the markingelements generates a dynamic signal which is essentially a square-wavesignal that fluctuates between a zero value and a maximum value. Adynamic signal has the advantage over a static signal in that it isimmediately recognizable whether the signal means is functional or not.An electronic analysis unit to analyze dynamic signals is preferablyprovided. This electronic analysis unit carries out a frequencyanalysis, for instance, on the above-described square-wave signal andcan thus determine the absence of a single pulse and thus of a singleflange element or bridge element and, in reaction thereto, put thesystem out of operation. The electronic analysis unit can be one that istypically used for such systems. Such electronic analysis units areavailable on the market, but they have only a relatively limited numberof signal inputs. For embodiments in which the ribs themselves are themarking elements, corresponding interruptions in the series of ribs canalso be provided.

Preferably, a sensor is provided on each side of the tread belt atessentially identical positions, the two sensors being connected inseries and connected to one input of the electronic analysis unit. Theseare sensors that pass on an input signal whenever they detect thepresence of a flange unit or a bridge unit; i.e., in case of successfuldetection by the first sensor, it passes the signal on to a secondsensor. If the latter can also successfully detect a bridge element or aflange element in the corresponding time interval, which is defined bythe length of the marking element, i.e., the clip or the rib, then thissignal is passed on to the electronic analysis unit. This type ofarrangement of the sensors requires a certain minimum length of the ribsor the marking elements so that there is a sufficiently long overlap ofthe signals from the sensors and has the advantage that only one inputof the electronic analysis unit is occupied for two (or possibly more)sensors.

On each flange element or bridge element, at least two marking elementsare preferably provided, for instance, one behind the other. Signals arethen favorably analyzed such that two signals must be missing before thesystem is shut down. If only one signal is missing, then a maintenancerequest is relayed to, for example, the nearest maintenance center. Thebackground for this is that it can certainly happen that, for instance,a contact gets lost or a signal is not detected. For the operator, sucha measure reduces very undesirable, pointless shutoffs to a minimum withminimal additional expense.

The invention and configurations of the invention will be describedbelow on the basis of a graphically represented embodiment. Shown are:

FIG. 1, a part of a people mover according to the invention, in whichparts have been broken away for a better representation; and

FIG. 2, a detail view of an escalator according to the invention.

In FIG. 1, one can recognize a people mover in the form of an escalator2, comprising an endless step belt 6 formed of several mutuallyconnected tread steps 4. The tread steps 4 are each connected toconveyance chains 8 provided at the sides. Connected “at the sides” isintended to include both embodiments in which the conveyance or stepchain[s] 8 are provided laterally alongside the tread steps 4 as seen ina plan view and those in which the step chains 8 are provided laterallyunderneath the tread surface 16 of a tread step 4 as seen in the planview. The conveyance chains 8 are formed from a plurality of chain links10. The chain links 10 are connected together at turning points 12. Alsoprovided at these turning points 12 are step chain rollers 14, whichguide the step chains 8 in step chain guides (not shown) along theclosed circulation path.

Step chain 2 is powered by a linear drive (not shown), which isconstructed in the manner of a linear drive formed by an endlessrevolving toothed drive belt. The toothing of the toothed drive beltengages with toothing 17 of chain links 10. The linear drive ispreferably arranged in the constantly inclined area of escalator 2. Asan alternative to the linear drive, it is also possible to provideconveyance chain 8 with a conventional drive unit in, for instance,upper or lower reversal point 22.

In FIG. 1, it is also recognizable that a tread element 4 has a treadsurface or “tread step” 16 as well as a front surface or “riser” 18. Onealso recognizes that an area of constant inclination is present, inwhich riser 18 essentially always has the same height. One alsorecognizes a transition area, in which riser 18 has an increasinglysmaller height, until it is finally no longer present just before areversal point 22, i.e., the individual tread elements or tread steps 4are arranged in one plane.

One also recognizes in FIG. 1 a concurrently moved side skirt 24, aswell as balustrade trim 26, which covers concurrently moved side skirt24 at the top and continues upwards from there. On top of trim 26, abalustrade made, for example, of glass can be placed, in which ahandrest (not shown) circulates essentially synchronously with step belt6.

Concurrently moved side skirt 24 comprises flange elements 28 havingessentially a semicircular shape that are mounted on tread elements 4.Between each two flange elements 28 there is provided a bridge element30 to fill out the space between them and to enable a movement ofconcurrently moved side skirt 24 from the constantly inclined areathrough the transition area into the landing area and from there via thereversal point to the return area. Flange elements 28 and bridgeelements 30 can be constructed to engage with one another in a type oftongue and groove joint, thus permitting relative motion with respect toone another. In place of balustrade trim 26 overlapping concurrentlymoved side skirt 24, a trim piece that more or less directly adjoinsconcurrently moved side skirt 24 at the top can also be provided and canbe engaged with concurrently moved side skirt 24 in similar manner bymeans of a tongue and groove joint.

Flange elements 28 are preferably formed integrally with tread elements4, typically from an aluminum material, with manufacture frompressure-cast aluminum being particularly favored. Bridge elements 30are also preferably formed from such a material. Ribs 32 and markingelements 34 in the form, for example, of spring steel clips 34 on flangeelements 28 and bridge elements 30 are shown only very schematically inFIG. 1. It is recognizable that these ribs and markers are arrangedessentially along a straight line in the constantly inclined area ofpeople mover 2 and form a continuous series 36 of ribs there.

In the enlarged detail view of FIG. 2, rib series 36 comprising ribs 32and spring steel clips 34 is more clearly recognizable. One can alsorecognize a schematically shown sensor 38, which is located between twospring clips 34 in the position shown. One recognizes in particular thatrib 32 on flange elements 28 is a section of peripheral rib 40 of flangeelements 28 that has been formed in a straight line. This is preferredfor reasons of manufacturing technology.

Spring steel clips 34 preferably consist of a magnetic spring steel. Itis also possible to glue essentially flat elements of magnetic materialto, for example, the rib or the inner side of flange elements 28 orbridge elements 30. The attachment of clamping elements is particularlysimple for reasons of operating and manufacturing technology, however,and is therefore preferred. For other than magnetic sensors 38, othersuitable marking materials can be provided. The marking materials canalso be provided in the ribs by, for instance, being cast in.Alternatively, the ribs themselves can be constructed such that theyrepresent appropriate marking elements. Measuring quite roughly, themarking elements or spring steel clips have roughly half the length ofthe associated flange elements 28 or bridge elements 30 at thecorresponding positions. Putting it in other terms, the signalsgenerated by a sensor 38 are preferably, roughly square-wave signalswith equal duration of the pauses and the individual signals. Themarking elements should have a predetermined minimum length to guaranteeassured detection and thus an assured signal. That is particularly thecase if two sensors 38 are arranged at the same height on differentsides of tread belt 6 in order to compensate for possible tolerances inthe arrangement of the sensors and the marking elements.

Spring steel clips 34 are preferably formed in essentially a U shape, sothat they can be fastened to rib 32 with the legs of the U grippinglaterally across rib 32. Barbs are preferably provided to preventdetachment of spring steel clips 34 from rib 32.

The sensors 38 can be mounted, for example, on the framework (not shown)of people mover 2, on the balustrade, on the rail system, on thehandrest drive unit or at other suitable positions. It is preferred toarrange at least one sensor pair on people mover 2 such that a missingflange element 28 or a missing bridge element 30 is discovered beforethe concurrently moved side skirt 24 at that point begins to move underbalustrade trim 26 or in some other manner into the return area. Thus itis assured that, if a “hole” exists, people mover 2 is stopped beforethe hole begins to get smaller. Since people movers 2 of the type showncan generally be moved in two directions, i.e., from left to right inFIG. 1 and from right to left, a corresponding pair of sensors should bearranged at both ends of the linear area of the people mover 2. The twosensor pairs are conceived especially to detect vandalism damage topeople mover 2 and, here in particular, bridge elements that haveslipped out of place. It is additionally favorable to place at least onesensor, better yet, a pair of sensors, in, for instance, the center ofthe return area, so as to be able to detect, in particular, missingflanges 28 and the resulting missing tread elements 4. In the returnarea it would be more favorable to provide a pair of sensors at eachreversal point 22 as in the forward motion area.

The sensors are connected to a suitable electronic analysis unit (notshown) that is connected to the control unit of system 2 and can shutdown people mover 2.

1. People mover (2) comprising: an endless tread belt (6) formed fromseveral tread elements (4) connected to one another, which is driven bya drive unit about a first and second reversal point (22); a side skirt(24) moved concurrently with the tread belt (6), the side skirt (24) onthe tread elements (4) comprising flange elements (28) joined to thetread belt and bridge elements (30) connected movably relative to theflange elements (28); a sensor (38) which is arranged adjacent to theside skirt (24), the sensor (38) having a limited detection rangeperpendicular to a circulating direction of the side skirt (24); and aplurality of marking elements (34) arranged in a line on the flangeelements (28) and the bridge elements (30) along the circulatingdirection and having a limited width perpendicular to the circulatingdirection.
 2. People mover (2) according to claim 1, wherein, on each ofthe flange elements (28) and bridge elements (30) of the side skirt(24), a rib (32) is provided that serves the detection of flange element(28) or bridge element (30) by sensor (38) and that is arranged on aside of the side skirt (24) that is opposite from the visible side. 3.People mover (2) according to claim 2, wherein the ribs (32) arearranged in series essentially along a straight line in a linear area ofpeople mover (2), the sensor (38) being constructed such that it detectsinterruption in the rib series (36).
 4. People mover (2) according toclaim 1, wherein the plurality of marking elements (34) is arranged in anon-continuous line along the flange elements (28) and the bridgeelements (30).
 5. People mover (2) according to one of claims 1-3,wherein two of the sensors (38) are connected in series.
 6. People mover(2) according to one of claims 1-3, wherein the plurality of markingelements (34) are clips and a clip (34) is provided for each flangeelement (28) or bridge element (30).
 7. People mover (2) according toone of claims 1-3, wherein the sensor (38) is a noncontact sensor. 8.People mover (2) according to claim 7, wherein the sensor (38) is amagnetic sensor.
 9. People mover (2) according to one of claims 2-3, theflange elements (28) and bridge elements (30) are manufactured fromaluminum material and the ribs (32) are constructed in one piecetherewith, and wherein the plurality of marking elements (34) are clipsand at least one clip of spring steel is provided on the rib (32) ofeach flange element (28) and each bridge element (30).
 10. People mover(2) according to claim 9, wherein the clips (34) are essentially half aslong as the corresponding ribs (32).